Here is my 12 gallon JBJ nano cube I am in the process of turning into a hammer dominated tank. The only modifications are adding the surface skimmer to the intake and upgrading the pump to a MJ900 with a Spinstream Rotating Nozzle. The first chamber in the rear is filler most of the way with a coarse sponge and the middle compartment is filled with Marinepure Biospheres, which I cannot say enough about. Currently stocked with a pair of bullet hole clownfish, royal gramma, and neon goby. I still need to move some things around and fill in the right side of my rock with more hammers but here is the progression so far.